ES2678124T3 - Device for dredging soil material underwater - Google Patents

Abstract

Device for pouring material on a bottom or underwater installation, such as a pipe, the device comprising: - a vessel (1), provided with a downpipe (2) through which the material is poured over the underwater bottom; - a steering device (5), adapted to control the movement of the downpipe (2) with respect to the underwater bottom; characterized in that the device additionally comprises: - first monitoring means (17, 30, 35), adapted to monitor the state of the underwater bottom; - second monitoring means (32, 36), adapted to monitor the position of the steering device (5) with respect to the background; and - recording means (33), adapted to record, based on the data (34, 39, 40) obtained from the first and / or second monitoring means, the control signals (42) to move the steering device ( 5).

Description

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DESCRIPTION

Device for dredging soil material underwater

The present invention relates to a device for pouring material on a bottom or underwater installation, such as a pipe. The invention also relates to a method for pouring material on a bottom or underwater installation, as well as a computer program comprising the instructions of the program, adapted to carry out the method.

The flowing media, for example, oil and gas, are normally transported over long distances through the pipes. To avoid costly detours, such pipes can be provided at the bottom of the sea, allowing the shortest distance between two locations to be covered. Such pipes must be adequately protected and for the entire distance they travel underwater. A useful method to protect the pipes involves the pouring of material (from the ground) onto the pipe, so that the pipe is really buried in material (from the ground).

A known device for pouring material on a bottom or underwater installation, such as a pipeline, is disclosed in GB 2004817A and comprises a vessel, provided with a downpipe through which the material is poured onto the underwater bottom. The downpipe moves along the underwater bottom by the impulse of the boat. The detailed movement of the downcomer with respect to the underwater bottom is normally controlled by a steering device fixed to the lower end of the downcomer. The ship's staff is the one that operates said steering device, also called a remote control vehicle or with its abbreviation ROV (for its acronym in English).

EP 2196622A1 discloses an underwater well intervention module and its placement on the well with an ROV. The ROV is used in the coupling procedure, in order to guide the module during its descent and secure the module over the wellhead, and to control the operation of intervention.

The discharge of materials, for example, quarry stones, at great depths (it is not uncommon for it to be 300 to 600 m) and, nevertheless, also at relatively small depths on the sea floor, poses difficulties such as the influence of currents , that the boat moves due to strong winds, etc. Since very large distances must be covered, it is important to be able to pour the material in the right place (on the pipe, for example) and also pour the material efficiently, which means that the profile of the desired underwater bottom has to achieved in as little time as possible and using as little material as possible.

An object of the present invention, therefore, is to overcome the disadvantages of the device and the method of the prior art mentioned above and to provide a device and method for pouring material on an underwater bottom that allows great operating efficiency.

In one aspect of the invention, there is thus provided a device for pouring material on a bottom or underwater installation, such as a pipe, the device comprising:

- a vessel, provided with a downpipe through which the material is poured over the underwater bottom;

- a steering device, adapted to control the movement of the downpipe with respect to the underwater bottom;

- first monitoring means, adapted to monitor the state of the underwater bottom;

- second monitoring means, adapted to monitor the position of the steering device with respect to the background; Y

- registration means, adapted to register, based on the data obtained from the first and / or second monitoring means, control signals to move the steering device.

The device according to the invention allows material to be poured quickly and accurately on a bottom or underwater installation, whereby the movement of the downpipe with respect to the bottom is automatically regulated, depending on the actual position of the steering device and the real state of the fund.

The invention also relates to a method for pouring material on a bottom or underwater installation, such as a pipeline, the method comprising the steps of:

- provide a device according to the invention

- pour the material into the underwater bottom through the pipe down the boat;

- control the movement of the downcomer with respect to the underwater bottom by means of the steering device;

- monitor the status of the underwater bottom and the position of the steering device with respect to the bottom; Y

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- register, based on the data obtained from this monitoring, the control signals to move the steering device; Y

- move the steering device (and the downpipe) in accordance with these control signals.

The method according to the invention is particularly useful for optimizing a spill operation along a spill line, that is, in an embodiment in which the vessel itself moves in a linear manner. The method of the invention substantially eliminates the variability associated with human action by providing a control loop, in which the movement of the steering device (and, therefore, also the movement of the downpipe and, in particular, from the mouth of the same) is controlled according to its real position and the real state of the fund.

In a further aspect of the invention, a device is provided in which the recording means are adapted to register the control signals to move the steering device, so that an optimal criterion is minimized. The optimal criteria can be selected at will. In a particularly favorable device, the optimal criterion comprises the difference between the real state of the fund, as measured by the first monitoring means, and a desired state of the fund.

The desired state of the bottom is usually determined before starting the pouring operation and, preferably, it has to do with its desired depth profile. For example, when a canalization has to be protected by covering it with (ground) material, the desired profile will normally be a strip of material with a determined width and height with respect to the natural underwater bottom and that the course of the canalization would follow. In this example, the desired depth of the strip of spilled material is less than the depth of the natural bottom. The state of the underwater bottom and, in particular, its depth profile can be determined beforehand by known techniques, such as by batimetna. The depth profile of the bottom during pouring is measured with the first monitoring means.

In another aspect of the invention, a device is provided in which the first monitoring means comprise an ultrasonic and / or optical camera. Said first monitoring means are preferably provided at the lower end of the downpipe and / or in the steering device, so that its distance from the underwater bottom is not too large. To this end, the steering device may be provided with extension structures, such as ailerons up to 5 m long or more, which carry the first monitoring means. The ultrasonic and / or optical camera can measure the depth profile of the underwater bottom in the area before, during or after the materials have been poured onto the underwater bottom. The means of ultrasonic and optical camera are already known. A particularly preferred optical camera comprises a multi-beam camera, which can be obtained in Reson®.

The second monitoring means are adapted to monitor the position of the steering device (and, therefore) also of the downpipe and, in particular, of the lower end of the downcomer where its mouth is located) with respect to the bottom. In this way, the movement of the vessel and / or the steering device can be related to the state of the submarine bottom as determined in a study, whose status includes, at least, the depth profile of the bottom. In fact, a study carried out before the actual start of the spill operation creates an initial depth profile of the natural submarine bottom and the uncovered facility, such as an open pipe. After the passage of the pipeline and knowing the amount of material (soil) poured, the new local depth can be calculated. By monitoring the position of the boat you get an updated depth profile. In a preferred aspect of the invention, a device is provided in which the second monitoring means comprise a general positioning system.

In another aspect of the invention, a device is provided comprising other monitoring means, adapted to measure the flow of the material sent through the downpipe and / or the speed of the boat. By combining the measured flow (in tons / min) with the speed of the boat (in m / min), the mass of material discharged per meter (in tons / m) of said device can be easily obtained.

In a preferred method according to the invention, the amount of material poured per meter of movement of the steering device is kept substantially constant. In another preferred method, the amount of material poured per meter of movement of the steering device is kept substantially constant by regulating the flow rate of the material sent through the downpipe with respect to the speed of the vessel.

In yet another aspect of the invention, not claimed, the device comprises an input / output device adapted to transmit the signals from the first and / or second and / or additional monitoring means to the recording means.

In another aspect of the invention but not claimed, the device comprises display units adapted to visualize the position of the steering device, the vessel and / or the state of the bottom, in particular, its depth profile. An operator of the downstream pipeline can thus supervise the spill operation and its progress.

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The foregoing and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims, taken together with the accompanying drawings, in which:

Figure 1 schematically shows part of a pouring vessel provided with a downpipe according to the invention;

Figure 2 schematically shows a detailed view of the steering device mounted on the lower end of the downpipe;

Figure 3 schematically shows a diagram of the device according to an embodiment of the invention;

Figure 4 schematically illustrates a possible scheme for carrying out the method according to the invention; Y

Figure 5 schematically illustrates the possible scheme of Figure 4 in a cross section.

With reference to figure 1, a pouring vessel 1 is shown. The vessel 1 is provided with a downpipe 2 which extends from the deck of the vessel 1, through the hull of the vessel 1 and towards the underwater bottom. At the height of the cover, a number of winches 3 are provided that carry a steering device 5 through cables 4. The steering device 5 forms the lower end of the downcomer 2 and is provided with drive means in the form of motors 6, whereby the steering device 5 and, therefore, the lower end of the downcomer 2 can move in directions that are substantially perpendicular to the longitudinal axis of the downcomer 2. The actual downcomer 2 comprises a series of tubular tubular elements 7 and, more particularly, cylindrical stacked on top of each other and supported by two or possibly more wires 10. Both ends of a cylindrical tubenade element 7 are arranged to fit against a corresponding end of a cylindrical element 7 adjacent. Each cylindrical tuben element 7 has adjoining flanges (8, 9) on its two ends that are directed outwardly. If desired, the annular space between the flanges (8, 9) adjoining two adjacent tubena elements 7 may be provided with a flexible seal (not shown) in the form of a separate rubber ring or by the extension of a polymeric inner liner. of the tubena elements 7 into the surface that adjoins an adjacent element 7. In this way, the downstream tubena 2 is provided with a certain elasticity that absorbs impacts and the like and also prevents too much water from entering into the downcomer pipe 2. Thus, the entire downcomer structure 2 is formed by different cylindrical elements 7. These elements 7 are trapped along the entire length of the downcomer 2 between two or more cables 10, which are fixed, more particularly, to the lowermost element of the downpipe 2. As a result of the weight of the different elements, these elements reside on each other so that they do not require nas strong connections between the different elements.

The lower end of the downpipe 2 is provided with a steering device 5, also referred to in the art as "remote control vehicle" or "ROV". This controllable remote steering device 5 comprises a central hopper 16 which is telescopically mounted with respect to the lowermost elements 7 of the downcomer pipe 2 and through which its material can be poured onto the underwater bottom. By means of cables 4, the turning movements of the ship can be compensated in such a way that the steering device 5 is placed at a constant distance from the underwater bottom. The steering device 5 is provided with folding support arms 18, which can extend up to 5 m or more and which are provided with first monitoring means, in the form of ultrasonic and / or optical sensors and / or cameras. To control the movement of the steering device 5 and, therefore, also the correct location of the lowermost end of the downpipe 2, driving means are provided in the steering device in the form of propellers 6. The movement of the steering device 5 is controlled by means of registration, as will be described in more detail below.

To pour the material, such as sand or quarry stones, for example, on the underwater bottom, said material, stored in the holds of the vessel 1, is transported through a conveyor 12 to the upper end of the downpipe 2 and it is poured inside, causing said material to fall through the downpipe 2 and the hopper 16 to reach the bottom.

As for Figure 3, the device according to the invention is provided with first monitoring means (17, 30, 35), adapted to monitor the state of the underwater bottom and, in particular, the depth profile of the bottom, and second monitoring means 32, adapted to monitor the position of the steering device 5 and / or of the vessel 1 with respect to the bottom. The embodiment shown of the device also includes other monitoring means 31, adapted to measure the flow of the material sent through the downpipe 2 and / or the speed of the vessel 1, and recording means 33 adapted to record, depending on the data (34, 39, 40) obtained from the first, second and preferably also from the additional monitoring means (17, 30, 35, 32, 31), the control signals 42 to move the steering device 5. The Signal transmission from the monitoring means to the recording means can be carried out by wiring (not shown) and / or wirelessly.

The first monitoring means (17, 30, 35) comprise several ultrasonic and / or optical sensors or cameras (17, see figure 2), mounted in various positions of the steering device 5 and, in particular, on the

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arms 18 thereof. The signals 34 generated by the ultrasonic and / or optical sensors 17 are transmitted through a suitable input / output device 35 to a first processing unit 30 of the monitoring means, comprising at least one memory for storing the depth profile signal data. If desired, the operator of the downpipe 2 and / or of the vessel 1 can display the depth profile of the bottom on a screen 40.

The second monitoring means (32, 36), adapted to monitor the position of the steering device and / or the vessel 1 with respect to the bottom, comprise a dynamic positioning system / dynamic tracking 32 (DP / DT). in English), already known, an input / output device 36, adapted to transmit the position signals from the second monitoring means, as well as the signals from the additional monitoring means, to the recording means 33, and a number of sensors of the steering device and / or of the position of the boat. The DP / DT 32 system allows the operator of the downstream pipeline to see on the line, through a display device 38, a graph of the depth profile of the bottom. Said profile is obtained by entering bathymetric data, obtained in advance, in the DP / DT 32 system. The depth profile of the bottom is updated in real time as a result of the pouring operation. The DP / DT 32 system also comprises a general positioning system, which allows to locate the general position of the vessel 1 and / or the steering device 5. When, through the steering device 5, the downpipe 2 is operated manually , the operator, in general, depends on the set of monitoring equipment described above. As the operator works below the water level, the visibility of the steering device 5 and the downpipe 2 is getting worse. Therefore, the operator needs to have real-time visualization of the position of the vessel 1 and, in particular, of the steering device 5 and the depth profile of the bottom, provided by the first monitoring means (30, 35) . When this information is combined with a signal of the general positioning system that comes from the DP / DT 32 system, a real-time visualization of the position of the steering device 5 with respect to the depth profile of the bottom is obtained.

In accordance with the invention, the additional monitoring means 31 are adapted to measure the flow of the material sent through the downcomer 2 and / or the speed of the vessel 1, and comprise several flow and / or speed sensors ( not shown), already known and which are normally incorporated in the downstream pipe 2 and in the vessel 1. The speed and flow signals (39, 40), which are emitted from the sensors, are transmitted through the input device / exit 36 to the registration means (31, 33) for further processing. If desired, a display unit 41 showing the flow and / or speed signals (39, 40) can be provided.

The recording means 33 are adapted for recording, based on the data 34 obtained from the first and / or second monitoring means (17, 30, 35) and / or the second monitoring means (32, 36), as well as in function of the data (39, 40) obtained from the additional monitoring means 31, the control signals 42 to move the address device 5. The control signals 42, emitted by the registration means 33, can also be displayed in a display unit 41.

Next, an embodiment of the invented method for pouring material on a bottom or underwater installation and for using the device described above is explained in more detail. Normally, a study of the depth profile of the aquatic bottom is carried out, firstly, by obtaining bathymetric data and for storing these in the DP / DT 32 system. This stage generates the information related to the depth profile 100 of the underwater bottom, as well as the position of the underwater installation, such as a pipeline 101, as shown in Figure 4 in a perspective view. The pipe 101 extends through the area in an x direction, perpendicular to the local cross-sectional (y, z) directions. Channeling 101 does not have to extend linearly (as shown), but may, for example, be curved. A desired depth profile is initially known and is shown in Figures 4 and 5 as depth profile 102. The material poured by the downpipe 2 will generally accumulate on the bottom as triangular shaped piles (102a, 102b, ...), which extend in the direction of vessel movement 1. Therefore, the desired depth profile 102 approximates several of said heaps (102a, 102b, ...), as shown in cross-section. in Figure 5. Note that the dimensions of the triangles (102a, 102b, ...) may vary along the longitudinal direction of the pipe 101, that is, in different x coordinates.

Thus, a vessel 1 is provided with a downstream pipe 2 and a steering device 5 are taken to a suitable starting location, and the downstream pipe 2 is lowered near the pipe 101 which must be protected, for example, in a lateral position 105, as shown in figure 5. In this way, the vessel 1 is configured in motion in the x direction with a velocity v, whereby the material is poured through the downcomer 2 with a flow rate Q The instantaneous address 104 of the vessel 1, in general, will deviate from the desired address due, for example, to local currents. According to the invention, the deviation is automatically corrected by moving the steering device 5 (and, therefore, the mouth of the downstream pipe 2) the same amount A and in the opposite direction (see Figure 5), so that the The mouth of the downcomer remains in the desired location 103. The desired location line 103 extends in the x direction and, for example, follows the curvatures of the pipe 101 to remain at the same distance from the pipe 101. The control signals 42 to move the address device 5 are registered with the registration means 33 in

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function of the input of the first, second and additional monitoring means (17, 30, 35, 32, 36, 31), which comprise at least the signal data of the instantaneous depth depth profile and the data of positioning of the steering device and / or of the vessel 1 with respect to the bottom, so that the optimum criterion is minimized. The optimal criterion in the given example comprises the difference between the real depth profile of the bottom (the initial depth profile being the profile 100), measured by the ultrasonic and / or optical sensors present in the steering device 5, and the profile desired depth of bottom. At the beginning of the pouring operation in this specific example, the difference between the actual and desired profile is represented and approximates with the set of heaps (102a, 102b, ...). Of course, after pouring some material, this may be different.

Minimizing the difference in this example involves pouring material according to a lot 102a in the x direction for a certain distance and then returning in the x direction to pour the monton 102b, and so when the amount of material poured per meter of movement of the steering device 5 in the x direction remains substantially constant, a lot (102a, 102b, ...) will be created with substantially the same cross section A. The cross section A, however, may change by varying the amount of material discharge per meter of movement x. This can be done either by varying the flow rate Q and / or by varying the speed v of the vessel.

The depth profile of the underwater bottom and the position of the steering device 5 with respect to the bottom are constantly monitored, as well as the flow rate Q of material through the downpipe and the speed v of the vessels, and these data are entered into the media of register 33 to register, based on the data obtained from this monitoring, control signals to move the steering device. The control signals actuate the thrusters 6 and their direction, so that the steering device 5 (and the downpipe 2) moves in the optimum direction Ay.

A desired pour profile depends on many properties, for example, on the underwater stability of the bottom and on the rheological properties of the spilled material. Other factors may be important, including boat stability, position control, tidal behavior and water currents and others. The device according to the invention allows to take into account a greater part of these parameters by providing a closed loop control system, in which the position and depth profile are combined to record the optimal control signals to move the steering device The invention is not limited to the choice of a particular optimal criterion and, in reality, any criteria that seems to be useful can be used.

The invention is not limited to any optimization algorithm and several can be used. Those skilled in the art know, in general, such algorithms and generally minimize some function f (x) subjected to a condition, such as h (x)> 0. In the present embodiment, the function f (x) comprises the difference of real and desired depth profile of the submarine bottom along the direction of movement of the vessel. The condition h (x)> 0, for example, may comprise the condition that the depth h (x) of the downpipe 2 is not greater than a given depth h1, the actual depth of the underwater bottom being. Thus, the condition becomes h (x) - h> 0 (when depths are given in negative numbers).

An optimization scheme is started by choosing initial values for x, and the Ax search addresses are registered using numerical algorithms, such as the well-known Newton method. Then, at another stage, it goes to another point and the calculations are repeated until the minimum is found. In the context of the present invention, the emission of the optimization scheme produces a subsequent movement of the steering device 5 of the downpipe 2, which basically comprises the horizontal movement, but sometimes also the vertical movement thereof, as well as the speed of movement. Thus, it is possible to maximize production and obtain a more uniform quality. The method and the device according to the invention also allow the depth profile previously obtained by the bathymetric data to be continuously updated.

The above disclosure has been set forth simply to illustrate the invention and is not intended to be limiting. It should be construed that the invention includes everything within the scope of the appended claims.

Claims (16)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. Device for pouring material on a bottom or underwater installation, such as a pipe, the device comprising: - a vessel (1), provided with a downpipe (2) through which the material is poured over the underwater bottom; - a steering device (5), adapted to control the movement of the downpipe (2) with respect to the underwater bottom; characterized in that the device further comprises: - first monitoring means (17, 30, 35), adapted to monitor the state of the underwater bottom; - second monitoring means (32, 36), adapted to monitor the position of the steering device (5) with respect to the background; Y - recording means (33), adapted to record, based on the data (34, 39, 40) obtained from the first and / or second monitoring means, the control signals (42) to move the steering device (5 ). 2. Device according to claim 1, wherein the recording means (33) are adapted to register the control signals (42) to move the steering device (5), so that an optimal criterion is minimized. 3. Device according to claim 2, wherein the optimum criterion comprises the difference between the actual state of the fund, as measured by the first monitoring means (17, 30, 35), and a desired state of the background. 4. Device according to claim 3, wherein the desired state of the bottom has to do with its depth profile and the first monitoring means (17, 30, 35) are adapted to measure the depth profile of the bottom. 5. Device according to any one of the preceding claims, wherein the first monitoring means (17, 30, 35) comprise an ultrasonic and / or optical camera. 6. Device according to any one of the preceding claims, wherein the second monitoring means (32, 36) comprises a general positioning system. 7. Device according to any one of the preceding claims, the device comprising additional monitoring means (17, 30, 35, 32, 31) adapted to measure the flow of the material sent through the downcomer and / or the speed of the boat. Device according to any one of the preceding claims, in which the steering device (5) is provided at the lower end of the downpipe (2) and comprises drive means (6). 9. Method for pouring material on a bottom or underwater installation, such as a pipeline, the method comprising the steps of: - providing a device according to any one of claims 1-8; - pour the material into the underwater bottom through the pipe down the boat; - control the movement of the downcomer with respect to the underwater bottom by means of the steering device; - monitor the status of the underwater bottom and the position of the steering device with respect to the bottom; Y - register, based on the data obtained from this monitoring, the control signals to move the steering device; Y - move the steering device (and the downpipe) in accordance with these control signals. 10. Method according to claim 9, wherein the control signals for moving the steering device are recorded so that an optimal criterion is minimized. 11. Method according to claim 10, wherein the optimal criterion comprises the difference between the actual state of the fund, as measured, and a desired state of the fund. 12. Method according to claim 11, wherein the desired state of the bottom has to do with its depth profile and the depth profile of the underwater bottom is monitored during pouring. 13. Method according to any one of claims 9-12, wherein the monitoring of the state of the underwater bottom is carried out with an ultrasonic and / or optical camera. 14. Method according to any one of claims 9-13, wherein the amount of material poured per 5 meter of movement of the steering device is kept substantially constant. 15. Method according to claim 14, wherein the amount of material poured per meter of movement of the steering device is kept substantially constant by regulating the flow rate of the material sent through the downcomer with respect to the speed of the ship. 10 16. Computer program comprising program instructions which, when loaded into a computer, performs the method according to any one of claims 9-15.